Apparatus for the synchronizing and shifting of rotating shiftable toothed elements



PERKINS ET AL 2,943,502

July 5, 1960 c. M.

APPARATUS FOR THE SYNCHRONIZING AND SHIFTING OF ROTATING SHIFTABLETOOTHED ELEMENTS p 17 Sheets-Sheet 1 Filed March 5, 1956 ww M 74W".

ATTORNEYS y 1960 c. M. PERKINS, ETAL 2,943,502

APPARATUS FOR THE SYNCHRONIZING AND SHIFTING OF ROTATING SHIFTABLETOOTHED ELEMENTS l7 Sheets-Sheet 4 Filed March 5, 1956 h\N ANN INVENTORSOwn [5 M. PiR/(l/VS BY 77/0/ 075 1 Ma-NQM/WFH Arron/2Y5 R mw July 5,1960 Filed March 5, 1956 c. M. PERKINS ETAL 2,943,502 APPARATUS FOR THESYNCHR ROTATING SHIFTABL ONIZING AND SHIFTING OF E TOOTHED ELEMENTS 1'7Sheets-Sheet 5 HTWRAE'YS July 5, 1960 c. M. PERKINS ETAL 2,943,502

APPARATUS FOR THE SYNCHRONIZING AND SHIFTING 0F ROTATING SHIFTABLETOOTHED ELEMENTS Filed March 5, 1956 17 Sheets-Sheet 6 ETTORNZ'YS July5, 1960 Filed March 5, 1956 M. PERKINS ETAL 2,943,502

C. APPARATUS FOR THE SYNCHRONIZING AND SHIFTING OF ROTATING SHIFTABLETOOTHED ELEMENTS 17 Sheets-Sheet 7 INVENTORS CHHRLZS M Paw/N5 ATTORNEYSJuly 5, 1960 c. M. PERKINS ETAL 2,943,502 APPARATUS FOR THESYNCHRONIZING AND SHIFTING OF ROTATING SHIFTABLE TOOTHED ELEMENTS FiledMarch 5, 1956 '17 Sheets-Sheet 8 HTTURNZ'YS y 1960 c M. PERKINS ETAL2,943,502

APPARATUS FOR IHE SYNCHRONIZING AND SHIFTING OF ROTATING SHIFTABLETOOTHED ELEMENTS Filed March 5, 1956 17 Sheets-Sheet 9 2/4; 3 226 2 e772 as? Arron/5 Y5 July 5, 1960 M PERKINS EI'AL 2,943,502

C. APPARATUS FOR THE SYNCHRONIZING AND SHIFTING OF ROTATING SHIF'TABLETOOTHED ELEMENTS Filed March 5, 1956 17 Sheets-Sheet 10 INVENTORS (HR/P44': M. Pun/vs July 5, 1960 c, ms ETAL 2,943,502

APPARATUS FOR THE SYNCHRONIZING AND SHIFTING OF ROTATING SHIFTABLETOOTHED ELEMENTS Filed March 5, 1956 1'7 Sheets-Sheet 11 INVENT0R$ 0mm:5 A1. Pam/v5 July 5, 1960 c. M. PERKINS ETAL APPARATUS FOR THESYNCHRONIZING AND SHIFTING OF ROTATING SHIFTABLE TOOTHED ELEMENTS l7Sheets-Sheet 12 Filed March 5, 1956 y 1960 c. M. PERKINS ETAL 2,943,502

APPARATUS FOR THE SYNCHRONIZING AND SHIFTING OF ROTATING SHIFTABLETOOTHED ELEMENTS 17 Sheets-Sheet 13 Filed March 5, 1956 INVENTORSCHE/FLA! M. Paw/N5 Two/m: K Maw/ 4mm ATTORNEYS c. M. PERKINS ETAL2,943,502 APPARATUS FOR THE SYNCHRONIZING AND SHIFTING 0F ROTATINGSHIFTABLE TOOTHED ELEMENTS July 5, 1960 17 Sheets-Sheet 14 Filed March5, 1956 NH QM IN V EN TORS [H/ML [5 A4. Paw/N5 HTTQRNEYS WWN y 1950 M.PERKINS ET AL 2,943,502

C. APPARATUS FOR THE SYNCHRONIZING AND, SHIFTiNG OF ROTATING SHIFTABLETOOTHED ELEMENTS Filed March 5, 1956 17 Sheets-Sheet 15 wmozam W '1 74 mATTORNEYS y 1950 c. M. PERKINS ET AL 2,943,502

APPARATUS FOR THE SYNCHRONIZING AND SHIFTING 0F ROTATING SHIFTABLETOOTHED ELEMENTS l7 Sheets-Sheet 16 Filed March 5, 1956 July 5, 1960 c.M. PERKINS ET AL 2,943,502

* APPARATUS FOR THE SYNCHRONIZING AND SHIFTING OF ROTATING SHIFTABLETOOTHED ELEMENTS Filed March 5, 1956 17 Sheets-Sheet 17 4g- 25 INVENTORSCHHRLES n1. Paw/vs Z/gzz H TTORNEYS Unit tats

APPARATUS FOR THE SYNCHRONIZING AND SHIFTING OF ROTA'I'ING SHIFTABLETOOTHED ELEMENTS Filed Mar. 5, 1956, Ser. No. 569,503

57 Claims. (Cl. 74-339) This invention relates to a method and apparatusfor the synchronizing of the speeds, and shifting, of shiftable rotatingtoothed elements.

In carrying out a program of steadily improving the design oftransmission devices, it is a constant objective to continually reduceboth the skill and the effort required of the operator in carrying out ashifting operation. This is a constant objective regardless of theparticular service involved, whether for passenger automobile use,commercial vehicle'use including heavy trucks, in earth movingequipment, cranes, mining machinery, or in any of the many othersituations wherein shiftable gearing is utilized. Particularly intransmissions for heavy duty use, such as in heavy trucks or earthmoving equipment, it is desirable to reduce as much as possible theskill and effort required of the driver in effecting a shift. On

the other hand, presently available fully automatic trans missionshavenot been entirely acceptable for certain uses, especially heavy dutybecause oftheir high original cost, their difiicult and expensivemaintenance requirements and their relative inflexibility to meetvarying operating conditions.

Therefore, it has long been desirable to provide for said certain uses,such as over-the-road operations, a power operated transmission whoseshifting is subject to easy manual selection, said selection beingcapable of being made by any of a variety of devices chosen to fit givenoperating conditions, as a push-pull rod, selectable push buttons orother convenient devices.

Further, recognizing the demand in connection with other uses, such, asin trucks designed to operate in congested trafiic, for fully automaticshifting operations, and the probable spreading of the demand therefor,it is equally desirable to provide a transmission capable of manualselection as above mentioned but which is of such basic design that itcan be readily adapted to fully automatic control if and when desired bythe simple addition of suitable controlling devices.

Turning now to the making of certain definitions, for the purpose ofclarity in discussion but with no intention to limit, it is known thattransmissions commonly employ a series of relatively shiftable,rotating, meshable members which are adapted to selectively mesh toprovide the desired ratio between the speed of rotation of the inputshaft of the transmission and the output shaft thereof. These membersmay be gears, jaw clutch parts, or other interengaging mechanicalmembers, and will be hereinafter collectively referred to as toothedelements. The term shifting and derivatives thereof shall refer to theact of moving one or more of the toothed elements into meshingengagement with other toothed, elements to obtain a desired speed ratiobetween the input and output shafts of the transmission. To obtain ameshing of a pair of the rotating toothedelements, it is desirable ned-1 2 .1.1960

2 I when they are rotating at such relative; speedsthat thejr respectivepitch circles, or corresponding parts, are travel; ing at precisely thesame circumferential rates, 'Ifhe proc; ess of bringing these rotatingtoothed elements to he meshed to such relative speeds (if-rotation shallbehereinafter referred to as synchronizing, The term con; dition ofsynchronization as used hereinaftershall; refer to a relative speedcondition of the toothed elements which may or may not bea condition ofjexact syn; chronization. The term acceptable condition ofjsynchronization as used hereinafter shall refer to any con; dition ofrelative speeds of the toothed elerrrents whieh will permit theirmeshing without excessive or unreasonas ble clashing.

One h mos r t antrb t no mean hacnly problem involved in providing atransmission for heavy duty operation, whether manually or:automatically controlled, is the problem of obtaining an acceptablecondition of synchronization of the toothed elements at the moment ofeffecting a shift. In a transmission intended for heavy duty operation,the toothed elements, shafts and other rotating parts involved are largeandt'hereby possessed of considerable inertia, This maltesthe'prohlem ofsynchronizing them during the process offs ifting materially moredifiicult, and by the same token"e,ven more important, than thecorresponding problem in Y missions intended for lighter duty, such as;in passe automobiles.

In the usual approach to transmission synchronization, means areprovided which are actuated at the instant; of exact synchronization andthe toothed elements/lobe meshed are then moved as rapidly asfpossibleinto meshing engagement with each other, the object beingltgeffect suchengagement as close as possible to the instant of exact synchronizationof the toothed elements to be meshed; This is satisfactory where aslight amount of time is permissible for accelerating or deceleratingthe toothed elements being driven by the input shaft during the shiftingoperation to bring them into, an accept ble condition of synchronizationwith the mating tooled elements connected to the output shaft so thatsuch are celerating and decelerating occurs at a relatively slow rate.However, in any type of operation where a large amount of, horsepower isbeing conducted through the transmission, as in a heavy truck, climbingafmountain grade, it is desirable to have the input shaft and outputshaft of" the transmission disconnected for as, period as possible andthis requires. a substantial s ing of the" rate of such accelerating anddecelerating. Thus, in order to speed the deceleration, of therotatingparts driven by the input shaft during an upshift, it as becomecustomary to use a deceleration, brake, I however, the rate of changeof, speed becomesjso rap that where shifting is started only upon exactsynchroi i i t' tion of the toothed elements to be, meshed, it isentirely possible for the meshable toothed elements. to. b entirely outof an acceptable condition of synchroni even during the fraction of asecond required forthe gears to move in response to the initiation ofthe; sh fting sequence. Previous efforts to avoid this diflicuity have,insofar as We are aware, been primarily dire ted toward increasing thespeed at which the toothed elements are moved toward each other uponthe. attainment of exact synchronization.

The present invention, however, approaches the. problem by detecting aparticular condition of synchronization slightly before, that is,in-anticipation of, exact synchronization and initiating the shiftingmovement at that time, the amount of such anticipation being chosen in agiven situation to cause the meshable toothedelments to enter intomeshable engagement with each other'suhstantially at, or slightly aheadof, the instant of exact synchronizaion of the speeds of rotationthereof.

A further problem with conventional equipment has been the problemarising out of disconnecting the engine from the input end of thetransmission by the conventional operation of the clutch. Withconventional equipment, this is necessary in order to enable thetransmission synchronizers to change the speed of the toothed element onthe engine side of any given pair of toothed elements to be engagedsufiiciently to enable such pair to attain an acceptable condition ofsynchronization, it being evident that the motion of the vehicle willkeep the proipeller shaft operating at a speed during any ordinaryshifting sequence which is not within the drivers control. Thus, unlessthe engine speed is increased or decreased sutficiently accurately tocorrespond to the change in speedof the input end of the transmissionbrought about by the shifting operation, either a great load will beplaced upon the clutch when it re-engages 'or an excessive load will beplaced upon the transmission parts. In an upshift, this is not tooserious since if the accelerator is merely released the engine speedwill diminish and thus it will change its speed in the same direction asthat which re-engagement of the clutch will bring about.

,However, in a downshift, this is not true and unless the accelerator isaccurately controlled to increase the engine speed by the proper amount,serious shock loads can occur.

Thus, by providing a system wherein the clutch can .remain engagedthroughout the'portion of a shifting operation comprising movement fromneutral to a shifted position, it becomes possible not only to effect amore stantially greater strain on the parts. On the other hand,

if the interengagement of the shiftable parts can be made while thetoothed element speeds are approaching exact synchronization, thenengagement of the toothed elements will assist synchronization.

Therefore, it is desirable to provide an apparatus, applicable to bothmanual and automatic shifting devices, which will anticipate the instantof exact synchronizajti'on "of the-toothed elements being mesheds'ufiiciently 'fthat by the time the shifting mechanism operates andactually brings the toothed elements into meshing engagement with eachother, their speeds will be in substantially exact synchronization,rather than in some indefinite condition not close to exactsynchronization. Further, since eifecting a shift exactly at the instantof exact synchronization for all conditions of operation is impossibleas a practical matter, it is desirable to provide means anticipating theinstant of exact synchronization 'and initiating a shifting operation asufiicient period of time prior thereto that the meshing'engagement ofthe toothed elements being shifted will occur slightly before the pointof exact synchronization. Thus, at the moment of engagement of thetoothed elements, their relative speeds will be approaching exactsynchronization rather than, as in present practice, moving away fromexact synchronization.

A still further problem involved in heavy duty transmissions is thatwhen manual shifting is carried out, the shift is often relatively slowbecause of the limited force available from the operators hand to effectthe shifting. In an operation involving the delivery of a large amountrapid shift, particularly in a downshift sequence, as 1 above set forthbut it also becomes possible to do so withof horsepower, such as where aheavy truck is climbing uphill, it is highly essential that theinterruption of the delivery of the power from the engine to the wheelsbe held to the shortest possible time interval. Thus, although fullyautomatic devices for elfecting such shifting are not desirable sincethey are not usually sufi'rciently flexible to meet the varying loadconditions imposed upon heavy duty equipment, a manually shifted devicedoes not ordinarily operate rapidly enough to prevent the engine shaftand the propeller shaft from being disconnected for an undesirablylongperiod of time. Accordingly, it is desirable to provide an apparatuswhich will be completely under manual control for each stage of itsoperation but wherein the. operation itself is carried out under powerso that it will be completed with a minimum period of-time whereintheengine shaft is disconnected irom the propeller shaft.

While primary reference has thus far been, and will herein continue tobe, made to heavy duty use, which for present purposes may be consideredto be all vehicular transmissions other than those for passenger cars,and including earth moving equipment, cranes, mining machinery, andsimilar equipment, and the research efforts resulting in the presentinvention have had in mind primarily heavy duty use, it should beclearly borne in mind that many of the problems solved by the presentinvention are also presentin passenger car use. Hence, many. of theobjects of the invention can be carried out in passenger carapplications and the scope of the invention should be interpretedaccordingly.

Likewise, while one primary purpose has been to provide a system oftransmission control which provides manual selection and power shifting,it will be understood that some of the; units developed for use with andin such system, particularly including the synchronizing method andapparatus but not .limited thereto, are also applicable to andadvantageous in other types of transmissions including an automatictransmissiom'and the portions of'the invention relating to such unitsshall be understood accordingly.

A major object of the invention is to provide a transmission shiftingdevice wherein all shifting operations will be subject to manualselection but will be eflfected by power.

A further object of the invention is to provide a device, as aforesaid,wherein the manual control requires relatively little skill or effort onthe part of the operator.

A further object of the invention is to provide a device, as aforesaid,in which the manual control may be moved into a desired position andthen left in that position without waiting for the shifting operation tobe completed, and the apparatus will then automatically complete theshifting operation without further attention on the part ofthe operator,excepting only that in a downshift operation the operator must increasethe engine speed sufliciently to make synchronization of the gearspossible.

A further object of the invention is to provide a. shifting systemsubject to manual control but carrying out the shifting operation underpower, which system will be adaptable for a use with a variety ofdifierent specific sources of power.

tuselfecting the shifting and will bring the toothed elements beingshifted into engagement with each other at a' point slightly ahead ofthe instant of exact synchronization.

A further object of the invention is to provide a device of thegeneraltype, as aforesaid, which will anticipate the instant of exactsynchronization of the toothed elements being shifted and will initiatesuch shifting at a point sufliciently prior to the instant of exactsynchronization that said elements will become i-nterengagedsubstantially at the instant of exact synchronization.

A further object of the invention is to provide a device, as aforesaid,wherein the time period by which the instant of exact synchronizationwill be anticipated by the apparatus initiating the shifting will be thesame for each of the available speed ratios of the transmission.

A further object of the invention is to provide a device, 'as aforesaid,which will automatically accommodate itself to either an upshift or adownshift and anticipate exact synchronization in either case.

A further object of the invention is to provide a device which will beoperable by a single, easily moved control which will require theoperators hand to be away from the other controls of the machineinvolved 'a minimum period of time or which may, if desired, be adaptedfor operation by the operator without requiring his hand to move fromthe other controls at all.

A further object of the invention is to provide a device, as aforesaid,which will be extremely rapid in operation and thereby effect shiftingsmoothly and with a minimum period of time during which the power fromthe engine to the propeller shaft is interrupted.

A further object of the invention is to provide a device, as aforesaid,in which the engine will remain connected to certain parts of thetransmission throughout the portion of a downshift shifting operationextending from the time the transmission parts are put into neutral'condition during the shift from the upper to the lower setting untilthe transmission parts reach their completely shifted position wherebythe engine may be utilized for changing the speed of the parts remainingso connected and thereby eliminate the shock to the driving system whichsometimes otherwise occurs upon the engagement of a previously releasedclutch. In prior practice such a previously released clutch sometimespermitted the engine and the propeller shaft driving parts of thetransposition from any shifted position, which mechanism involves only asingle pressure fluid cylinder.

A further object of the invention'is to provide pressure fluid shiftingapparatus for a transmission in which pressure fliiid may be applied tothe apparatus for eflfecting the next shift to be made and includingshift preventing means preventing engagement of the toothed elements inresponse to said pressure until the toothed elements to be engaged havereached a predetermined condition of synchronization.

A further object of the invention is to provide apparatus in which saidshift preventing means and the means returning the 'main transmission toits neutral position during each shifting operation are the sameapparatus.

It is a further object ofthe invention to provide a device wherein thenext shifting operation is 'pre-energi zed but the shifting movement isblocked until the toothed elements to be engaged have reached adesirable and predetermined condition of synchronization. When suchcondition is reached, the blocking condition is removed and the partswill then move with a minimum time requirement into the next shiftedposition.

"A furtherobject of the invention is to provide a method, as aforesaid,which can be carried out by a variety of different typesofapparatus,particularly'prcssure fluid apparatus or electrical apparatus, asdesired,

- to meet the requirements of a particular operation.

A further object of the invention is to provide a method for effectingshifting of a transmission which can be carriedout 'by relatively simpleapparatus.

A further object of the invention is to provide apparatus of the typeaforesaid which will be positive and reliable in operation, which willbe rugged, and which will not require excessive maintenance.

A further object of the invention is to provide a transmission of thegeneral type aforesaid wherein the parts carrying the heavy load arerelatively simple and of well known nature and the parts most likely torequire maintenance are relatively small and can, if necessary, bereadily removed and replaced bodily.

A further object of the invention is to provide apparatus of the typeaforesaid which'can be readily serviced by mechanics of ordinary abilityand, at least for the most part, by the use of ordinary tools.

A further object of the invention is to provide a device, as aforesaid,wherein the specially made parts are all relatively easy to fabricateand thereby economical to manufacture.

Other objects and purposes of the invention will become apparent topersons acquainted with this general type of apparatus upon reading thefollowing specification and examining the accompanying drawings.

in the drawings:

Figure 1 is a schematic representation of a fluid energized form ofapparatus embodying the invention and representing same in its neutralcondition.

Figure 2 is a central cross sectional view of a detector unit adaptedfor utilization with the apparatus shown in Figure 1.

Figure 2a shows a tooth pattern provided between certain of the partsshown in Figure 2, and is a sectional view taken on line lla lIa ofFigure 2.v

Figure 3 is a sectional view taken on the line III III of Figure 2. Y

Figure 4 is a schematic representation similar to Figure 1 and showingthe apparatus in the position corresponding to the commencement of ashift out of neutral position and into first gear.

Figure Sis a representation similar to a portion of Figure 4 and showingsuch portion of the -apparatus after the manual trip valve has beenactuated incident t0 the Shift from neutral to, fiISt gear by moving thecontrol rod for the control valve into first gear position.

Figure 6 is a representation similar to Figure 1 and showing theapparatus with the shift into first gear completed.

Figure 7 is a representation similar to Figure l and showing theapparatus in a condition as it is shifted from first gear position tosecond gear position wherein the control rod is in intermediate positionbetween first gear position and second gear position.

Figure 8 is a representation similar to Figure 1 and showing the controlrod in second gear position and the transmission parts partially movedout of first gear position toward neutral as the shift from first gearto second gear progresses.

Figure 9 is a representation similar to Figure 1 and showing thetransmission parts returned to full neutral position as they move fromfirst gear to second gear position.

Figure 10 is a representation similar to a portion of Figure 8 andshowing the position of the Pats of the detector unit after the toothedelements therewitbin have shifted to their second gear position butprior to movement of any of the parts associated with the maintransmission toward second gear.

Figure 11 is a representation similar to Figure -1 and

